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  <title>Check for numeric character(s)</title>

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</div><hr /><div id="function.ctype-digit" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">ctype_digit</h1>
  <p class="verinfo">(PHP 4 &gt;= 4.0.4, PHP 5)</p><p class="refpurpose"><span class="refname">ctype_digit</span> &mdash; <span class="dc-title">Check for numeric character(s)</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.ctype-digit-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="type">bool</span> <span class="methodname"><strong>ctype_digit</strong></span>
    ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$text</code></span>
   )</div>

  <p class="para rdfs-comment">
   Checks if all of the characters in the provided <span class="type"><a href="language.types.string.html" class="type string">string</a></span>,
   <em><code class="parameter">text</code></em>, are numerical.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.ctype-digit-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<em><code class="parameter">text</code></em></dt>

     <dd>

      <p class="para">
       The tested string.
      </p>
     </dd>

    
   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.ctype-digit-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns <strong><code>TRUE</code></strong> if every character in the string
   <em><code class="parameter">text</code></em> is a decimal digit, <strong><code>FALSE</code></strong> otherwise.
  </p>
 </div>


 <div class="refsect1 changelog" id="refsect1-function.ctype-digit-changelog">
  <h3 class="title">更新日志</h3>
  <p class="para">
   <table class="doctable informaltable">
    
     <thead>
      <tr>
       <th>版本</th>
       <th>说明</th>
      </tr>

     </thead>

     <tbody class="tbody">
      <tr>
       <td>5.1.0</td>
       <td>
        Before PHP 5.1.0, this function returned <strong><code>TRUE</code></strong>
        when <em><code class="parameter">text</code></em> was an empty string.
       </td>
      </tr>

     </tbody>
    
   </table>

  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.ctype-digit-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-4977">
    <p><strong>Example #1 A <span class="function"><strong>ctype_digit()</strong></span> example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$strings&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">'1820.20'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'10002'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'wsl!12'</span><span style="color: #007700">);<br />foreach&nbsp;(</span><span style="color: #0000BB">$strings&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$testcase</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">ctype_digit</span><span style="color: #007700">(</span><span style="color: #0000BB">$testcase</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"The&nbsp;string&nbsp;</span><span style="color: #0000BB">$testcase</span><span style="color: #DD0000">&nbsp;consists&nbsp;of&nbsp;all&nbsp;digits.\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}&nbsp;else&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"The&nbsp;string&nbsp;</span><span style="color: #0000BB">$testcase</span><span style="color: #DD0000">&nbsp;does&nbsp;not&nbsp;consist&nbsp;of&nbsp;all&nbsp;digits.\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
The string 1820.20 does not consist of all digits.
The string 10002 consists of all digits.
The string wsl!12 does not consist of all digits.
</pre></div>
    </div>
   </div>
  </p>
  <p class="para">
   <div class="example" id="example-4978">
    <p><strong>Example #2 A <span class="function"><strong>ctype_digit()</strong></span> example comparing strings with integers</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br />$numeric_string&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'42'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$integer&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">42</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">ctype_digit</span><span style="color: #007700">(</span><span style="color: #0000BB">$numeric_string</span><span style="color: #007700">);&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;true<br /></span><span style="color: #0000BB">ctype_digit</span><span style="color: #007700">(</span><span style="color: #0000BB">$integer</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;false&nbsp;(ASCII&nbsp;42&nbsp;is&nbsp;the&nbsp;*&nbsp;character)<br /><br /></span><span style="color: #0000BB">is_numeric</span><span style="color: #007700">(</span><span style="color: #0000BB">$numeric_string</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;true<br /></span><span style="color: #0000BB">is_numeric</span><span style="color: #007700">(</span><span style="color: #0000BB">$integer</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;true<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
 </div>


 <div class="refsect1 notes" id="refsect1-function.ctype-digit-notes">
  <h3 class="title">注释</h3>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <p class="para">
    This function expects a <span class="type"><a href="language.types.string.html" class="type string">string</a></span> to be useful, so for example passing
    in an <span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span> may not return the expected result. However, also note that
    HTML forms will result in numeric strings and not integers. See also the
    <a href="language.types.html" class="link">types</a> section of the manual. 
   </p>
  </p></blockquote>
  <blockquote class="note"><p><strong class="note">Note</strong>: <p class="para">
如果给出一个 -128 到 255 之间(含)的整数, 将会被解释为该值对应的ASCII字符 (负值将加上 256 以支持扩展ASCII字符).
其它整数将会被解释为该值对应的十进制字符串.</p></p></blockquote>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.ctype-digit-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.ctype-alnum.html" class="function" rel="rdfs-seeAlso">ctype_alnum()</a> - Check for alphanumeric character(s)</span></li>
    <li class="member"><span class="function"><a href="function.ctype-xdigit.html" class="function" rel="rdfs-seeAlso">ctype_xdigit()</a> - Check for character(s) representing a hexadecimal digit</span></li>
    <li class="member"><span class="function"><a href="function.is-numeric.html" class="function" rel="rdfs-seeAlso">is_numeric()</a> - 检测变量是否为数字或数字字符串</span></li>
    <li class="member"><span class="function"><a href="function.is-int.html" class="function" rel="rdfs-seeAlso">is_int()</a> - 检测变量是否是整数</span></li>
    <li class="member"><span class="function"><a href="function.is-string.html" class="function" rel="rdfs-seeAlso">is_string()</a> - 检测变量是否是字符串</span></li>
   </ul>
  </p>
 </div>

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